Besides the fact that they are novel, the compounds of the present invention have particularly advantageous properties by selectively binding to the 5-HT.sub.2C serotoninergic receptors with respect to the 5-HT.sub.2A receptors. This novel property has never been demonstrated for the most closely related compounds of the prior art such as, for example, those described in patents WO 9006927, EP 410,535, EP 539,209 or EP 95666.